Isolated hypohidrosis: pathogenesis and treatment.

BACKGROUND: Hypohidrosis can result in heat injury, a potentially fatal condition. The majority of hypohidrosis cases have no associated abnormalities or secondary causes, and are termed "isolated hypohidrosis". These are clinically divided into miliaria profunda (MP), acquired idiopathic generalized anhidrosis (AIGA) and idiopathic partial hypohidrosis (IPH). The pathogenesis of isolated hypohidrosis remains largely unknown and there is no established effective treatment. OBJECTIVES: To elucidate the pathogenesis of isolated hypohidrosis using in vivo high-definition optical coherence tomography (HD-OCT) imaging and assess the therapeutic profile of oral retinoids for this condition. MATERIALS & METHODS: We conducted a retrospective analysis on all patients with isolated hypohidrosis in our neuro-dermatology clinic over a 5.75-year period. All patients routinely underwent standardised exercising and whole-body starch-iodine testing, followed by non-invasive HD-OCT skin imaging. Patients' demographics, disease characteristics, histology and treatment history were analysed. RESULTS: Of the 51 patients identified with isolated hypohidrosis; 23 were diagnosed with MP, 14 with AIGA, and 14 with IPH. In these patients, HD-OCT imaging led to the identification of sub-stratum corneal hypo-refractile material with underlying dilated sweat ducts, not present in healthy controls. The size of this material was most pronounced in MP, followed by AIGA, and then IPH. Post-treatment, the material decreased in size. Treatment response was reported in 90.6% patients with isotretinoin and 75.0% with acitretin. No recurrence has been reported to date. Side effects were largely anticipated and common. CONCLUSION: The pathogenesis of isolated hypohidrosis involves obstruction of sweat orifices at the stratum corneum. Treatment with oral retinoids, particularly isotretinoin, is effective and safe.

Congenital insensitivity to pain and anhidrosis: Case report and review of findings along neuro-immune axis in the disorder.

Congenital insensitivity to pain and anhidrosis (CIPA) is one of the hereditary autonomic and sensory neuropathies. Typically presenting in infancy, it manifests as hyperpyrexia from defects in sweating (autonomic) and self-mutilating injuries from pain insensitivity (sensory). CIPA being rare in North America, diagnosis is often missed due to variable presentation. Subsequent management of its complications is therefore delayed. We report an unusual presentation in a 2-year-old girl with preexisting diagnosis of CIPA who was evaluated for bilateral upper extremity paresis of insidious onset. MRI revealed a mass compressing her cervical spine as the cause, and work up suggested immune dysfunction as possible etiology. To our knowledge, this complication has not been reported before in association with the disease. We introduce the disease by explaining the molecular pathology behind its presenting features. The neurological findings, documented in association with CIPA, are summarized and serve as a reference for the various presentations of this rare disorder. Since this disease is known to affect the immune system, immune defects in CIPA are discussed with recommendations for surveillance of patient's immune status.

Hypohidrotic ectodermal dysplasia: prenatal diagnosis by three-dimensional ultrasonography.

Ectodermal dysplasia is the term used to describe a group of rare congenital anomalies characterized by abnormal development of 1 or several ectoderm-derived tissues. At least 154 different types, divided into 11 clinical subgroups, have been recognized. Among them, the hypohidrotic type is the most common form, with an incidence of 1 per 10,000 to 1 per 100,000 live births. This condition, originally known as anhidrotic ectodermal dysplasia because of the notable reduction of sweat gland function, is clinically characterized by hypohidrosis, hypotrichosis, and hypodontia. Most cases are inherited as an X-linked recessive trait, with the gene responsible being mapped to Xq12-q13.1. The autosomal recessive and dominant patterns of inheritance have also been documented. Prenatal diagnosis of this condition has been reported previously in high-risk pregnancies on the basis of histologic analysis of fetal skin obtained by second-trimester fetoscopy-guided skin biopsy. DNA-based linkage analysis has also made the diagnosis possible with the use of chorionic villi in the first trimester. In this report, we describe noninvasive prenatal diagnosis of hypohidrotic ectodermal dysplasia in a pregnancy at risk for this condition. The diagnosis was achieved by identification of the distinct facial features at 30 weeks' gestation on three-dimensional (3D) ultrasonography.

Cardiac sympathetic denervation in Ross syndrome demonstrated by MIBG-SPECT.

We investigated cardiac sympathetic innervation by metaiodobenzylguanidine (MIBG) imaging in a patient with tonic pupils, loss of tendon reflexes, and segmental anhidrosis (Ross syndrome). Despite normal cardiovascular reflex tests, we observed a reduced global myocardial MIBG uptake as well as a regional uptake defect over the posterolateral cardiac territory indicating left ventricular peripheral sympathetic denervation. MIBG imaging seems to be a useful noninvasive diagnostic method for detection of early--possibly subclinical--cardiac autonomic impairment in Ross syndrome and provides further evidence of injury to postganglionic autonomic neurons as the underlying pathological mechanism of the disease.